JP4575500B2 - Video signal processing apparatus, control method therefor, and television signal receiving apparatus - Google Patents

Description

  The present invention relates to a video signal processing apparatus, a control method therefor, and a television signal receiving apparatus.

  In recent years, digital video signal compression / decoding processing is performed in a digital video signal recording / playback device and digital video signal transmission / reception device. As a compression encoding / decoding system for digital video signals, for example, the MPEG (Moving Picture Experts Group) 2 system is known.

  It is known that block noise occurs when a digital video signal compressed and encoded by the MPEG2 system is decoded. This block noise is conspicuous as a luminance error in a plain area of the image.

  In order to reduce such noise, there is a technique of image processing and an image processing method for performing smoothing processing on a video signal (for example, Patent Document 1).

  On the other hand, a technique has been developed that performs sharpness processing of high-frequency components and can emphasize the sharpness difference of an image even on a large-screen display (for example, Patent Document 2).

JP 2008-160440 A JP 2007-324664 A

  In the technique of Patent Document 1 in which the smoothing process is executed for noise reduction, the characteristic is always set to obtain a constant smoothing effect. For this reason, the smoothing process may not function effectively depending on the contents of the pattern.

  Moreover, in order to sharpen an image, it is contrary to performing sharpness processing for a high frequency component as in Patent Document 2 and performing smoothing processing for noise reduction as in Patent Document 1. Have a part. Since the conventional techniques deal with individual problems, there are cases where the comprehensive functions that can be exhibited by the assembled video signal processing apparatus cannot be predicted and noise is emphasized.

  Therefore, in one aspect of the present invention, a video signal processing apparatus, a control method thereof, and a video signal processing apparatus capable of performing an appropriate smoothing process by obtaining an adaptive operation according to the frequency component of the input digital video signal. An object of the present invention is to provide a television signal receiving apparatus.

  In another aspect of the present invention, even when sharpness processing is performed on a high frequency component, an appropriate smoothing processing is performed in conjunction with the sharpness processing, and a video signal processing apparatus capable of obtaining a comprehensive improvement in image quality. It is another object of the present invention to provide a control method thereof and a television signal receiving apparatus.

In the present invention, a smoothing block that reduces a gradation difference of a plane area, which is an image area of a low frequency band of an input digital video signal, according to a parameter, and a plurality of bands when determining the frequency state of the input digital video signal As the first case , the lower frequency component lower than the frequency set in advance as the first case is less than the higher frequency component, and the second case as the second case. A frequency state determination block for obtaining a determination result of a case where the frequency component on the low frequency side lower than the preset frequency is higher than the frequency component on the high frequency side, and when the determination result is the second case, A correction parameter output for outputting a correction parameter for enhancing the smoothing processing of the smoothing block as compared with the case of the first case. Having a block.

  Further, in the present invention, when the determination result is the second case, the sharpness processing of the sharpness block preceding the smoothing block is enhanced by the correction parameter as compared with the case of the first case. Is also possible.

  According to the above solution, according to the present invention, the operation of the smoothing process performs an adaptive operation according to the frequency component of the input digital video signal, so that unnecessary noise is hardly generated. In addition, when sharpness processing for high frequency components is executed by adding a sharpness block and its adaptive operation, appropriate smoothing processing can be executed in conjunction with this to obtain a comprehensive improvement in image quality. .

1 is a configuration explanatory diagram of a video signal processing apparatus according to an embodiment of the present invention. FIG. It is explanatory drawing which shows each part characteristic shown in order to demonstrate the operation | movement and function of the video signal processing apparatus of FIG. It is a figure which shows the structural example of the frequency state determination block 113a of FIG. It is a figure which shows the structural example of the calculating part 200 of FIG. It is a figure which shows the basic structural example of the gradation smoothing block 120b of FIG. It is a figure which shows the structural example of the micro change extraction part of FIG. It is a figure which shows the example of the input / output characteristic of a micro amount extraction part in the circuit of FIG. 1 is an overall block diagram of a digital television broadcast receiver to which the present invention is applied.

  Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 shows an embodiment of the present invention. A digital luminance signal Y is input to an input terminal 101, a color difference signal Cb or Pb is input to an input terminal 102, and a color difference signal Cr or Pr is input to an input terminal 103.

  The luminance signal Y and the color difference signals Cb / Pb and Cr / Pr are input to the sharpening / gradation smoothing processing unit 120. The sharpening / gradation smoothing processing unit 120 includes a sharpness block 120a that performs sharpening processing of a digital video signal, and a gradation smoothing block 120b that performs smoothing processing on the output of the sharpness block 120a.

  Further, the luminance signal Y of the input terminal 101 is input to the frequency analysis / correction parameter generation unit 113. The frequency analysis / correction parameter generation unit 113 acquires a correction parameter 115 corresponding to the frequency distribution of the input digital video signal. For this purpose, the frequency analysis / correction parameter generation unit 113 includes a frequency state determination block 113a and a correction parameter output block 113b for determining the frequency distribution state from the histogram of the input digital video signal.

  The correction parameters output from the correction parameter output block 113b are input to adders 116 and 117 serving as correction units.

  The adder 116 adds the correction parameter to the sharpness initial parameter, and gives it to the sharpness block 120a. As a result, the degree of enhancement of the high frequency component of the sharpness block 120a is controlled to increase or decrease. On the other hand, the adder 117 adds the correction parameter to the smoothing initial parameter, and gives it to the gradation smoothing block 120b. Thereby, in the gradation smoothing block 120b, the degree of the smoothing process is emphasized or alleviated.

  As described above, the sharpness block 120a increases the sharpness and improves the image quality when it is determined that the input digital video signal has a low high frequency portion. At this time, noise in the low frequency part (a plain area of the video) is also worsened as a side effect. Therefore, in the gradation smoothing block 120b, the correction parameter is used as offset data for the smoothing initial parameter, and the calculation result is the actual smoothing process. Smoothing parameter. Therefore, the gradation smoothing block 120b performs a smoothing process using actual smoothing parameters.

  The sharpening / gradation smoothing processing unit 120 outputs the finally obtained luminance signal Y ′, color difference signals Cb ′ / Pb ′, Cr ′ / Pr ′ to the output terminals 121, 122, 123.

  By adopting the above-described configuration, even if there is a case where noise is deteriorated because the sharpness processing is interlocked to adapt to the input frequency distribution, the smoothing processing can be applied at the same time. Therefore, the influence of noise deterioration on the final output can be suppressed.

  Further explanation is added. The sharpness block 120a obtains histogram data of the input digital video signal and performs high-frequency emphasis processing according to the frequency distribution of the input signal.

  Here, the gradation smoothing block 120b performs a smoothing process on a plain area of a video signal, and it is known that this is effective for stripes and block noise due to gradation degradation. However, if a parameter that emphasizes the effect is selected and fixed, there is a problem that the image is totally blurred.

  Therefore, in the present invention, when high-frequency emphasis linked to the detection result of the frequency distribution is performed as described above, by using the detection result to offset the tone smoothing parameter to be stronger, This is to enhance the area and suppress the deterioration of noise in the plain part of the video signal.

  In the above description, the luminance signal Y system has been described, but it goes without saying that the same processing may be performed on the color difference signal (Cb (Pb) / Cr (Pr)).

  FIG. 2 is an explanatory diagram of characteristics and operation characteristics showing characteristic operations of the apparatus shown in FIG. The characteristic diagrams 211 and 212 in FIG. 2 show Example 1 and Example 2 of the frequency distribution of the input digital video signal determined by frequency analysis in the frequency state determination block 113a.

  The characteristic diagram 211 (example 1) shows that, as a result of the analysis, there are few low frequency components lower than about 1/2 of the entire frequency band of the input digital video signal, and many high frequency components. Show. The characteristic diagram 212 (example 2) shows that, as a result of analysis, there are many low frequency components lower than approximately 1/2 of the entire frequency band of the input digital video signal, and there are few high frequency components. Is shown.

Next, the operation characteristic diagram 213 shows the operation characteristic of the sharpness block 120a. The vertical axis is the sharpness emphasis direction set by parameters, the lower direction is softening, the upper direction indicates the degree of sharpening, the horizontal axis is the frequency distribution, the left side is the direction in which high frequency components increase, the right side is The high frequency component is reduced. Furthermore, the operation characteristic diagram 214 shows the operation characteristic of the gradation smoothing block 120b. The vertical axis is the smoothing degree direction set by the parameter, the lower direction is smoothing, the upper direction is the degree of noisy, the horizontal axis is the frequency distribution, the left side is the direction in which high frequency components increase, the right side Is the direction in which the high frequency component decreases.

  In the operation characteristic diagram 213, a characteristic line 213a is a characteristic based on a sharpness initial parameter. When only this characteristic line 213a is used, the degree of sharpness is kept almost constant regardless of the frequency distribution.

  In the operation characteristic diagram 214, a characteristic line 214a is a characteristic based on the smoothing initial parameter. When only this characteristic line 214a is used, the degree of smoothing is kept almost constant regardless of the frequency distribution.

  According to the present invention, the sharpness block 120a performs the sharpness process using the characteristic line 213b. In the gradation smoothing block 120b, smoothing processing is performed using the characteristic line 214b.

  That is, in the sharpness block 120a, in the case of a signal with many high frequency components, it is not necessary to emphasize the high frequency with the sharpness default. Therefore, the sharpness initial parameter is maintained as a parameter when a signal with a lot of high frequency components is input. However, when a signal with few high-frequency components is input, the degree of sharpness processing is emphasized to improve the image quality (see the characteristic line 213b). In this case, the correction parameter is added to the sharpness initial parameter, and the sharpness is enhanced.

  However, as a result of emphasizing the sharpness, block noise originally hidden in the low frequency component tends to deteriorate, and the S / N of the low frequency component tends to deteriorate.

  Therefore, the gradation line smoothing block 120b employs the characteristic line 214b. That is, in the case of a signal with a lot of high frequency components, since the sharpness enhancement processing is not performed, it can be considered that the low frequency noise has not deteriorated. Therefore, the smoothing initial parameter is maintained when a signal having many high frequency components is input. However, when a signal with a low high frequency component is input, a correction parameter is added to the smoothing initial parameter in order to reduce the deterioration of the block noise and the S / N of the low frequency component. Smoothing processing is enhanced.

  Here, threshold values 1 and 2 are set for the changing point of the characteristic line 213b. Also, threshold values 1 and 2 are set for the changing point of the characteristic line 214b.

  In order to prevent the output video from changing sharply at the transition point of state determination with many / small high-frequency components, a plurality of threshold values such as threshold values 1 and 2 are used for offset processing of parameters as control data. This is because the image quality is gradually changed between two or more points.

  As described above, the conventional smoothing processing method does not have dynamic control with respect to various conditions of the input video, and always has a constant effect for any scene. However, more effective smoothing can be performed by setting different parameters depending on the scene conditions.

  Therefore, in the present invention, when the function of increasing the image quality setting in conjunction with the frequency distribution detection result as described above is used, it is possible to suppress the generation of noise by simultaneously offsetting the gradation creation parameter more strongly. . In other words, the occurrence of block noise can be suppressed by applying strong smoothing at the same time even when the input digital video signal is raised with a high frequency and a sharpness.

  The present invention is not limited to the above embodiments. FIG. 3 shows a configuration example of the frequency state determination block 113a. Luminance signal Y is input to a plurality of bandpass filters 104, 105, 106, 107, and 108 having different pass frequency bands and subjected to frequency decomposition. Then, each luminance signal component is input to the calculation unit 200, weighted for each band signal, and output as frequency state determination data. This frequency state determination data is input to the correction parameter output block 113b and converted into a correction parameter.

  FIG. 4 shows a configuration example of the arithmetic unit 200. The frequency-resolved signals in each band are weighted by coefficient units 201, 202, 203, 204, and 205, respectively. The weighting is performed so that the ratio can be easily determined when the ratio of the low frequency component and the high frequency component are compared. In the example of the figure, the outputs of the coefficient units 201, 202, 203, and 204 are added by the adder 211, the output of the coefficient unit 205 is input to the adder 212, and the outputs of the adders 211 and 212 are the comparators. This is a configuration compared at 213. Here, by adjusting the weighting values in the coefficient units 201, 202, 203, 204, and 205, it is possible to change the criterion for determining the magnitude relationship between the output of the adder 211 and the output of the adder 212. This criterion is set based on, for example, statistical data acquired by the designer when various digital video signals are subjected to signal processing in the design stage. Therefore, an adjustment block for adjusting the weighting value may exist, or a switching block may be provided so that the filter output taken into the adders 211 and 212 can be changed.

  The outputs from the adders 211 and 212 are input to the comparator 213 and the subtracter 214. The subtracter 214 takes the difference value. This difference value indicates the amount of change in the frequency distribution state. This change amount data is effective for generating a correction parameter between the threshold value 1 and the threshold value 2 described in FIG. The state determination data output from the comparator 213 determines the state of the characteristic diagram 1 or characteristic diagram 2 described with reference to FIG.

  The state determination data and the change amount data are input to the correction parameter output block 113b. The correction parameter output block 113b includes, for example, a memory or an arithmetic circuit having a look-up table for outputting correction parameters based on the state determination data and the change amount data.

  The sharpness block is configured such that, for example, an input digital video signal is separated into a high frequency component and a low frequency component, and the high frequency component can be emphasized according to a parameter. And it is a block which synthesize | combines the emphasized high frequency component and the low frequency component isolate | separated previously. High frequency components are extracted by a digital differentiation circuit, and low frequency components are extracted by a digital filter circuit.

  Next, a basic configuration example and an operation example of the gradation smoothing block 120b will be described with reference to FIGS. In FIG. 5, the input luminance signal Y is subjected to the smoothing process for the gradation difference in the vertical direction by the vertical direction processing unit 701, and then subjected to the smoothing process for the gradation difference in the horizontal direction by the horizontal direction processing unit 801.

  The vertical processing unit 701 includes, for example, a delay circuit 710 for eight lines, minute change extraction units 711, 712, 713, and 714, and an averaging unit 715 that rounds the outputs of the minute change extraction units 711 to 714. The horizontal processing unit 801 includes, for example, a delay circuit 810 for 8 pixels, minute change extraction units 811, 812, 813, and 814, and an averaging unit 815 that rounds the outputs of the minute change extraction units 811 to 814.

  The vertical correction data VE output from the averaging unit 715 of the vertical direction processing unit 701 is input to the subtractor 716. The subtractor 716 subtracts the correction data VE from the center data A0 to obtain an output luminance signal Y1 smoothed in the vertical direction. The luminance signal Y1 is input to the horizontal direction processing unit 801 and supplied to the subtracter 816 as the correction data HE in the horizontal direction. The subtractor 816 subtracts the horizontal direction HE from the center data B0 to obtain an output luminance signal Y2.

  In the vertical direction processing unit 701, the minute change extraction unit 711 is inputted with the center data A0, the data A + 4 at a position separated by 4 lines from the center data A0 in the plus / minus direction, and the data A-4. . The minute change extraction unit 712 basically detects the difference between the center data A0 and the data A + 4 and the difference between the center data A0 and the data A-4, and determines whether there is a difference between pixels in the gradation. The difference of the smaller one is taken out. The minute change extraction unit 712 receives the center data A0, the data A + 3 at a position separated from the center data A0 by three lines in the plus / minus direction, and the data A-3. The minute change extraction unit 713 receives the center data A0, the data A + 2 at a position separated from the center data A0 by two lines in the plus / minus direction, and the data A-2. The minute change extraction unit 714 receives center data A0, data A + 1 at a position one line away from the center data A0 in the plus / minus direction, and data A-1. Each minute change extraction unit 712-714 also basically detects the difference between the center data A0 and one data, the difference between the center data A0 and the other data, and whether there is a difference between pixels in the gradation. Judgment is made and the smaller difference is extracted.

  The outputs of the minute change extraction units 711-714 are added by the averaging unit 715, and the average value is output as the previous correction data VE.

  In the horizontal direction processing unit 801, the minute change extraction unit 811 is inputted with the center data B0, data B + 4 at a position separated by 4 pixels from the center data B0 in the plus / minus direction, and data B-4. . The minute change extraction unit 812 basically detects the difference between the center data B0 and the data B + 4 and the difference between the center data B0 and the data B-4, and determines whether there is a difference between the pixels in the gradation. The difference of the smaller one is taken out. The minute change extraction unit 812 receives the center data B0, the data B + 3 at a position separated from the center data B0 by 3 pixels in the plus / minus direction, and the data B-3. The minute change extraction unit 813 is inputted with the center data B0, data B + 2 at a position that is two pixels away from the center data B0 in the plus / minus direction, and data B-2. The minute change extraction unit 814 receives center data B0, data B + 1 at a position one pixel away from the center data B0 in the plus / minus direction, and data B-1. Each minute change extraction unit 812-814 also basically detects the difference between the center data B0 and one data, or the difference between the center data B0 and the other data, and whether there is a difference between pixels in the gradation. Judgment is made and the smaller difference is extracted.

  The outputs of the minute change extraction units 811-814 are added by the averaging unit 815, and the average value is output as the previous correction data HE.

  The above processing corresponds to detecting a change in gradation in units of 8 × 8 pixels and performing a smoothing process so that the change is not noticeable when there is a change in gradation. That is, block noise is reduced.

  Here, a parameter is given to the minute change extraction unit. FIG. 6 shows a configuration example of one minute change extraction unit as a representative. The minute change extraction unit receives the center data A0, data A + I at a position separated from the center data A0 by I (line or pixel) in the plus or minus direction, and data A-I. I is any one of 1 to 4. The difference between the data A0 and A-I is calculated by the subtracter 901, converted to an absolute value by the absolute value circuit 904, and input to the selector 907. The difference between the data A0 and A + I is calculated by the subtracter 902, converted to an absolute value by the absolute value circuit 905, and input to the selector 907. The difference between the data A0 and A + I is calculated by the subtracter 902, converted to an absolute value by the absolute value circuit 905, and input to the selector 907. The selector 907 selects one of the smaller ones and supplies it to the minute amount extraction unit 908.

  The difference between the data A-I and A + I is calculated by a subtracter 903, converted into an absolute value by an absolute value circuit 906, and the absolute value is supplied to a minute amount extraction unit 909. The difference between the data A-I and A + I indicates whether the level change of the pixel rises to the right, rises to the left, or no change.

As the above detection pattern, the following patterns can be considered: AI <A0, A0 <A + I, AI <A + I (rising upward)
Pattern 2 ... AI> A0, A0> A + I, AI> A + I (down shoulder)
Pattern 3 ... AI <A0, A0> A + I, AI = A + I (triangle)
Pattern 4 ... AI> A0, A0 <A + I, AI = A + I (inverted triangle type)
The input / output characteristics of the minute amount extraction units 908 and 909 are controlled by the parameters from the previous adder 110. The outputs of the minute amount extraction units 908 and 909 are input to the minimum value detection unit 911, and the smaller one is selected. The selected data is input to the code reproduction unit 912 to reproduce the code, and is adopted as correction data.

  Here, the initial state of the relationship between the input Vi and the output Vo of the minute amount extraction units 908 and 909 is set as shown in FIG. First, as the value of input Vi increases from zero, output Vo increases at a constant rate until it reaches V1. When the value of the input Vi is from V1 to V2, the output Vo is maintained at a constant value Vout1. When the value of the input Vi exceeds V2, the output Vo changes in a decreasing direction.

  As a result, the smoothing processing effect is gradually strengthened until the value of the input Vi becomes V1, the smoothing processing effect is maintained (not changed) from V1 to V2, and the smoothing processing effect is weakened when V2 or higher. The reason why Vout is constant when the input Vi value is V1 to V2 is that noise is likely to occur if the smoothing effect changes frequently. The reason why the smoothing processing effect is weakened when V2 or higher is that there is a high possibility that it is different from the original tone smoothing target picture.

  Here, in the adder 110, when the correction parameter described with reference to FIG. 1 is added to the initial parameter, the relationship between the input Vi and the output Vo of the minute amount extraction units 908 and 909 is, for example, FIG. The conversion characteristics are as shown in FIG. With this characteristic, the sensitivity of changing the output Vo with respect to the input Vi is increased. For this reason, the gradation smoothing processing circuit 112 shown in FIG. 1 operates so as to increase the sensitivity at the time of fade-in and fade-out, and reduce the gradation step portion in the plane area.

  FIG. 8 schematically shows a signal processing system of a television signal receiving apparatus in which the video signal processing apparatus of the present invention is incorporated.

  The main configuration of the video signal processing apparatus is incorporated in the signal processing unit 34 and controlled by the control unit 35. The digital television broadcast signal received by the digital television broadcast receiving antenna 22 is supplied to the tuner 24 via the input terminal 23. The tuner 24 selects and demodulates a signal of a desired channel from the input digital television broadcast signal. The signal output from the tuner 24 is supplied to the decoder 25 and subjected to MPEG (moving picture experts group) 2 decoding processing including the MPEG decoder 41, for example.

  The output of the tuner 24 is directly supplied to the selector 26. It is also possible to separate video / audio information from this signal and record the video / audio information in a recording device (not shown) via the control unit 35.

  Further, the analog television broadcast signal received by the analog television broadcast receiving antenna 27 is supplied to the tuner 29 via the input terminal 28. The tuner 29 selects and demodulates a signal of a desired channel from the input analog television broadcast signal. The signal output from the tuner 29 is digitized by an A / D (analog / digital) converter 30 and then output to the selector 26.

  The analog video and audio signals supplied to the analog signal input terminal 31 are supplied to the A / D converter 32 and digitized, and then output to the selector 26. Further, the digital video and audio signals supplied to the digital signal input terminal 33 are supplied to the selector 26 as they are.

  When the A / D converted signal is recorded by the recording device, the MPEG encoder 42 attached to the selector 26 performs compression processing in a predetermined format, for example, MPEG (moving picture experts group) 2 system. After that, it is recorded by a recording device.

  The selector 26 selects one of the four input digital video and audio signals and supplies it to the signal processing unit 34. The signal processing unit 34 performs predetermined signal processing on the input digital video signal and supplies it to the video display 14. As the video display unit 14, for example, a flat panel display such as a liquid crystal display or a plasma display is adopted. The signal processing unit 34 performs predetermined signal processing on the input digital audio signal, converts the signal into an analog signal, and outputs the analog signal to the speaker 15 to perform audio reproduction.

  Here, in the television signal receiving apparatus, various operations including the various receiving operations described above are comprehensively controlled by the control unit 35. The control unit 35 is a microprocessor with a built-in CPU (central processing unit) and the like, and receives operation information from the operation unit 16 and an operator (not shown) or operation information transmitted from the remote controller 17. By receiving and processing the light receiving unit 18, each unit is controlled so that the operation content is reflected.

  In this case, the control unit 35 uses the memory 36. This memory 36 mainly includes a ROM (read only memory) storing a control program executed by the CPU, a RAM (random access memory) for providing a work area to the CPU, various setting information and control information. And the like are stored in a nonvolatile memory.

  Of course, a processing system for a plurality of signals operating in parallel has a built-in time adjustment buffer so that synchronization can be obtained. In the above description, the processing system for converting the luminance signal is shown, but it goes without saying that a gradation smoothing block may be provided in each of the color difference signal system and the color signal system. Further, although the 8 × 8 pixel block has been described as the minute change detection range, the present invention is not limited to this, and various modifications such as a 4 × 4 pixel block and a 16 × 16 pixel block may be designed. Of course, the circuits may be combined.

  As described above, the present invention is useful when applied to a video signal processing apparatus, a television signal receiving apparatus, a recording / reproducing apparatus, a set top box, and the like.

  113 ... Frequency analysis / correction parameter generation unit, 113a ... Frequency state determination block, 113b ... Correction parameter output block, 116, 117 ... Adder, 120 ... Sharpening / gradation smoothing processing Part, 120a ... sharpness block, 120b ... gradation smoothing block.

Claims (7)

A smoothing block that reduces a gradation difference of a plane area, which is an image area of a low frequency band of an input digital video signal, according to a parameter;
When determining the frequency state of the input digital video signal , frequency decomposition is performed on a plurality of bands and components of each band are used, so that a frequency component on a low frequency side lower than a frequency set in advance as a first case is obtained. A frequency state determination block for obtaining a determination result in a case where there are fewer frequency components on the higher frequency side, and in a second case, the frequency components on the lower frequency side lower than the preset frequency are higher than the frequency components on the higher frequency side When,
When the determination result is the second case, the video signal includes a correction parameter output block that outputs a correction parameter that enhances the smoothing process of the smoothing block as compared with the case of the first case. Processing equipment.   When the determination result is the second case, the sharpness processing of the sharpness block in the previous stage of the smoothing block is enhanced by the correction parameter as compared with the case of the first case. Item 2. The video signal processing device according to Item 1.   3. The video signal processing apparatus according to claim 2, wherein when the determination result is the first case, the sharpness processing of the sharpness block and the smoothing processing of the smoothing block are executed according to initial parameters.   The video signal processing apparatus according to claim 1, wherein the frequency state determination block is capable of adjusting a preset frequency to a higher side and a lower side.   The frequency state determination block, when determining the frequency state, extracts frequency components of a plurality of different frequency bands from the input digital video signal, and weights each extracted frequency component for determination. Item 5. The video signal processing apparatus according to Item 4. The tone difference between the sharpness block that emphasizes the high frequency component of the input digital video signal in accordance with the first parameter and the plane area that is the low frequency band image area of the output digital video signal from this sharpness block is the second. In the control method of the video signal processing apparatus for controlling the smoothing block to be reduced according to the parameter of
When determining the frequency state of the input digital video signal , frequency decomposition is performed on a plurality of bands and components of each band are used, so that a frequency component on a low frequency side lower than a frequency set in advance as a first case is obtained. The case where there are fewer frequency components on the higher frequency side, and the second case outputs the determination result of the case where the frequency component on the lower frequency side lower than the preset frequency is higher than the frequency component on the higher frequency side,
When the determination result is the second case, a correction parameter for the first and second parameters is generated, the sharpness processing of the sharpness block is enhanced compared to the case of the first case, and the A control method for a video signal processing apparatus characterized by enhancing smoothing processing of a smoothing block. A decoder that receives a broadcast signal, decodes the received signal and outputs a digital video signal, a signal processing device that performs predetermined signal processing on the digital video signal, and a video signal processed by the signal processing device In a television signal receiving apparatus having a display unit for displaying and a control unit that controls signal processing operations,
The signal processing device includes:
A sharpness block that enhances the high frequency component of the input digital video signal according to the first parameter;
A smoothing block for reducing a gradation difference of a plane region, which is an image region of a low frequency band of an output digital video signal from the sharpness block, according to a second parameter;
When determining the frequency state of the input digital video signal , frequency decomposition on a plurality of bands is performed and components of each band are used, so that the frequency component on the low frequency side lower than the frequency set in advance as the first case can be obtained. Frequency state determination for obtaining a determination result in a case where there are fewer frequency components on the high frequency side than this, and in a second case, the frequency components on the low frequency side lower than the preset frequency are higher than the frequency components on the high frequency side Block,
If the determination result is the second case, a correction parameter for the first and second parameters is generated to enhance the sharpness processing of the sharpness block than in the first case; and A television signal receiving apparatus comprising: a correction parameter output block for enhancing a smoothing process of the smoothing block.

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